Habit

You may send SMS after call

PERMISSIONS:
In addition to basic permissions, MyOperator app needs access to other functions on your device for it to support the above features:
IGNORE BATTERY OPTIMIZATIONS: Since Habit is a “Task Automation App”, and its core function is scheduling automated actions, such as sending SMS after calls.

ACCESSIBILITY SETTINGS:
After installation kindly turn on accessibility settings from Settings > Accessibility
From the apps shown in the list turn Habit setting to "ON".
This setting helps the app to start automatically in case of phone restart.